U.S. patent number 5,419,687 [Application Number 08/202,954] was granted by the patent office on 1995-05-30 for fluid pump and suction pump assembly including same.
Invention is credited to Carmeli Adahan.
United States Patent |
5,419,687 |
Adahan |
May 30, 1995 |
Fluid pump and suction pump assembly including same
Abstract
A fluid pump includes a housing constituted of a base integrally
formed with an annular wall defining a fluid reservoir and carrying
an electrical pumping device, and a casing enclosing the pumping
device. One side of the casing is open and is attached to the base.
The opposite side of the casing is closed but includes an opening
snugly receiving the annular wall of the fluid reservoir for
rigidifying the housing. The pumping device includes a bellows
attached at one end to the annular wall and at the opposite end to
a push rod coupled by a crank to an electrical motor.
Inventors: |
Adahan; Carmeli (Ramot 3,
Jerusalem, IL) |
Family
ID: |
22751892 |
Appl.
No.: |
08/202,954 |
Filed: |
February 28, 1994 |
Current U.S.
Class: |
417/412;
417/472 |
Current CPC
Class: |
A61M
1/82 (20210501); A61M 1/0023 (20130101); F04B
45/02 (20130101); F04B 39/1073 (20130101) |
Current International
Class: |
A61M
1/00 (20060101); F04B 45/00 (20060101); F04B
45/02 (20060101); F04B 39/10 (20060101); F04B
017/00 () |
Field of
Search: |
;417/413R,412,472 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gluck; Richard E.
Attorney, Agent or Firm: Ladas & Parry
Claims
I claim:
1. A fluid pump comprising:
a housing having a fluid reservoir formed at one end with a fluid
inlet port, and at the opposite end with a fluid outlet port;
an annular wall defining said fluid reservoir between the two
ports;
a pumping device including an electrical motor for pumping a fluid
into said fluid reservoir via a pumping opening in said annular
wall;
and a valve assembly within said fluid reservoir producing a
positive pressure at one of said ports and a negative pressure at
the other of said ports;
characterized in that said housing includes:
a cover integrally formed with said reservoir and carrying said
electrical motor;
and a casing enclosing said motor and pumping device;
one side of said casing being open and attached to said cover, an
opposite side of the casing being closed but including an opening
snugly receiving said annular wall of the fluid reservoir for
rigidifying the housing.
2. The fluid pump according to claim 1, wherein said pumping device
includes a single bellow attached at one end to said annular wall
to enclose said pumping opening therethrough leading into said
fluid reservoir; the opposite end of said single bellow being
coupled to a push rod which is reciprocated by said motor to pump
fluid via said pumping opening with respect to said fluid
reservoir.
3. A fluid pump comprising:
a housing having a fluid reservoir formed at one end with a fluid
inlet port, and at the opposite end with a fluid outlet port;
an annular wall defining said fluid reservoir between the two
ports;
a pumping device including an electrical motor for pumping a fluid
into said fluid reservoir via a pumping opening in said annular
wall;
and a valve assembly within said fluid reservoir producing a
positive pressure at one of said ports and a negative pressure at
the other of said ports;
characterized in that said pumping device includes a single bellow
attached at one end to said annular wall to enclose said pumping
opening therethrough leading into said fluid reservoir; the
opposite end of said single bellow being coupled to a push rod
which is reciprocated by said motor to pump fluid via said pumping
opening with respect to said fluid reservoir.
4. The fluid pump according to claim 3, wherein said push-rod is
unguided between its attachment to said motor and its attachment to
said single bellow.
5. The fluid pump according to claim 4, wherein said bellow is
formed with side wall sections joined by an annular juncture
section, said annular juncture section being of greater thickness
than said side wall sections such as to impart to the bellow a low
yielding resistance in the axial direction, and a higher yielding
resistance in the lateral direction.
6. The fluid pump according to claim 4, wherein said one end of the
single bellow is formed with a relatively thick annular bead
received within an annular groove formed in said annular wall of
the fluid reservoir, and said opposite end of the single bellow is
formed with a relatively thick annular bead received within an
annular socket formed in the respective end of said push rod.
7. The fluid pump according to claim 1, wherein said cover is
integrally formed with a mounting for said electric motor, said
electric motor mounting comprising a edge formed with a large
recess for accommodating an eccentric coupled to the motor, and a
pair of smaller recesses for receiving motor fastening screws.
8. The fluid pump according to claim 1, wherein said valve assembly
includes a first one-way valve carried by a first mounting member
press-fitted into said annular wall of the fluid reservoir on one
side of said pumping opening; and a second one-way valve carried by
a second mounting member press-fitted into said annular wall of the
fluid reservoir on the other side of said pumping opening.
9. The fluid pump according to claim 8, wherein one of said valve
mounting members is formed with a pin, and the other of said valve
mounting members is formed with a hole receiving said pin with a
press-fit.
10. The fluid pump according to claim 1, wherein said annular wail
of the fluid reservoir includes a muffler member press-fitted into
the end thereof defining said positive-pressure port.
11. The fluid pump according to claim 1, wherein the bottom of said
pump housing is formed with semi-circular grooves extending
transversely across its opposite ends, each of said grooves
receiving a cylindrical bead of elastomeric material to define
supporting feet at said opposite ends of the housing.
12. A suction pump assembly including a fluid pump according to
claim 1, wherein its cover is further formed with a socket for
receiving an attachment connector carried by a liquid collection
container; and a liquid collection container having a connector for
reception into said socket of the pump base.
13. The suction pump assembly according to claim 12, wherein said
liquid collection container includes a housing closed at its upper
end by a cover of resilient material; said cover being integrally
formed with a a vacuum port having an axis at an acute angle with
respect to the cover, and with a liquid inlet port also having an
axis at an acute angle with respect to the cover.
14. The suction pump assembly according to claim 13, wherein said
vacuum inlet port includes an overflow shutoff valve
comprising:
a floatable shutoff section closed at one end and open at its
opposite end;
a mounting section for mounting the shutoff section with its closed
end facing the vacuum inlet port and its open end facing the
interior of the container;
and a yieldable juncture section integrally formed with said
mounting section and said shutoff section, normally maintaining the
shutoff section spaced from the vacuum inlet port, but permitting
the shutoff section to close the vacuum inlet port when the liquid
collected in the container reaches a predetermined level.
15. The suction pump assembly according to claim 14, wherein said
cover of the container is integrally formed with a pair of
depending pins adjacent to said vacuum inlet port, and said
mounting section of the overflow shutoff valve is formed with a
pair of eyelets receiving said depending pins with a press-fit.
16. The suction pump assembly according to claim 12, wherein said
housing includes opposed side walls and a bottom wall formed with a
projection on its inner surface, and a spacer wall received over
said projection and extending completely across the width of the
container in engagement with the inner surface of said opposed side
walls.
17. The suction pump assembly according to claim 16, wherein one
end of said spacer wall is of T-configuration to engage an enlarged
surface of the respective side wall.
18. The suction pump assembly according to claim 16, wherein said
liquid collection container engages said positive-pressure port to
thereby muffle the air passing therethrough to the atmosphere.
Description
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a fluid pump which can be
constructed to operate either as a suction pump or as a compressor.
The invention is particularly useful in suction pump assemblies for
drawing off waste fluids, for example in medical applications, and
is therefore described below with respect to such application.
Many constructions have been developed for fluid pumps particularly
useful in medical applications for drawing off waste fluids.
Examples of such pumping devices are described in my prior U.S.
Pat. Nos. 4,726,745 and 5,116,206. The fluid pump described in the
first patent is based on the use of a rolling diaphragm; whereas
the pump described in the second patent utilizes a piston
reciprocated within a cylinder.
An object of the present invention is to provide a fluid pump which
may be constructed of a few relatively simple parts and which can
be produced and assembled in volume and at relatively low cost.
Another object of the invention is to provide a suction pump
assembly including the novel fluid pump and also a liquid
collection container to be attached to the fluid pump. A further
object is to provide a liquid collection container of a novel
construction providing a number of important advantages.
BRIEF SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided
a fluid pump comprising: a housing having a fluid reservoir formed
at one end with a fluid inlet port, and at the opposite end with a
fluid outlet port; an annular wall defining the fluid reservoir
between the two ports; a pumping device including an electrical
motor for pumping a fluid into the fluid reservoir via a pumping
opening in the annular wall; and a valve assembly within the fluid
reservoir producing a positive pressure at one of the ports and a
negative pressure at the other of the ports. The housing includes a
cover integrally formed with the reservoir and carrying the
electrical motor, and a casing enclosing the motor and pumping
device. One side of the casing is open and is attached to the
cover. An opposite side of the casing is closed but includes an
opening snugly receiving the annular wall of the fluid reservoir
for rigidifying the housing.
According to further features in the preferred embodiments of the
invention described below, the pumping device includes a single
bellow attached at one end to the annular wall to enclose the
pumping opening therethrough leading into the fluid reservoir. The
opposite end of the single bellow is coupled to a push rod which is
reciprocated by the motor to pump fluid via the pumping opening
into and out of the single bellow.
More particularly, in the described preferred embodiments, the
single bellow is formed with side walls joined by an annular
juncture. The annular juncture is of greater thickness than the
side walls such as to impart to the single bellow a low yielding
resistance in the axial direction, and a higher yielding resistance
in the lateral direction.
A fluid pump constructed in accordance with the foregoing features
requires but a few simple parts which can be produced and assembled
in volume and at relatively low cost.
According to a further aspect of the invention, there is provided a
liquid collection container particularly useful with the fluid pump
and including an overflow shutoff valve comprising an annular
shutoff section closed at one end and open at its opposite end; a
mounting section for mounting the shutoff section with its closed
end facing the vacuum inlet port of the container and its open end
facing the interior of the container; and a yieldable juncture
section integrally formed with the mounting section and the shutoff
section, normally maintaining the shutoff section spaced from the
vacuum inlet port, but permitting the shutoff section to close the
vacuum inlet port when the liquid collected in the container
reaches a predetermined level.
According to further features in the described preferred
embodiment, the cover of the container is integrally formed with a
pair of depending pins adjacent to the vacuum inlet port, and the
mounting section of the overflow shutoff valve is formed with a
pair of eyelets receiving the depending pins with a press-fit.
Further features and advantages of the invention will be apparent
from the description below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with
reference to the accompanying drawings, wherein:
FIG. 1 is a view partly in section illustrating one form of suction
pump assembly constructed in accordance with the present invention,
including a fluid pump and a liquid collection container attached
thereto;
FIG. 2 is a sectional view illustrating only the liquid collection
container of the assembly of FIG. 1; and
FIG. 3 is a sectional view illustrating the fluid pump of FIG. 1
but with the valve assembly changed so that the pump serves as a
compressor rather than as a suction pump.
DESCRIPTION OF PREFERRED EMBODIMENTS
The fluid pump illustrated in the drawings may be used either as a
suction pump or as a compressor by merely making a slight change in
a valve assembly. FIGS. 1 and 2 illustrate the fluid pump used as a
suction pump; whereas FIG. 3 illustrates the same construction with
a slight modification to enable it to be used as a compressor.
The Embodiment of FIGS. 1 and 2
The suction pump illustrated in FIG. 1, therein generally
designated 2, is part of suction pump assembly which includes a
liquid collection container, generally designated 4, for drawing
off waste fluids, e.g., in medical applications. FIG. 2 more
particularly illustrates the construction of the liquid collection
container 4.
The suction pump 2 comprises a cover 10 and a casing 12 attached to
the cover in any suitable manner, e.g., as by fasteners shown at 14
in FIG. 2. Cover 10 is of moulded plastic material integrally
formed with an annular wall 16, preferably of cylindrical
configuration, defining a vacuum reservoir 8. Cover 10 is further
integrally formed with a pair of spaced ledges, one of which is
shown at 18 in FIG. 1, for mounting an electrical motor 20. The two
ledges 18 are formed with a large semi-circular recess 18a
centrally of the ledges for accommodating the eccentric 22 of motor
20, and with a pair of smaller semi-circular recesses 18b on
opposite sides of the central recess 18a for receiving screws 24
which fasten motor 20 to ledge 18.
Motor 20 drives a bellows 26 via a push rod 28 fixed at one end to
the bellows, and at the opposite end to eccentric crank 22 via ball
bearing 30. The single bellow 26 is fixed to the inner wall 16 of
the fluid reservoir 18 to enclose a pumping opening 32 formed in
wall 16. It will thus be seen that reciprocation of push rod 28 by
the rotation of the motor drive shaft 22 will drive bellows 16
through contraction and expansion strokes with respect to the
pumping opening 32 and the vacuum reservoir 8.
Single bellow 26 is made of an elastomeric material, such as
rubber. It is constituted of opposed side wall sections 26a, 26b
joined by an annular juncture section 26c extending peripherally
around the side wall sections. The two side wall sections 26a, 26b
are relatively thin, whereas the annular juncture section 26c is of
greater thickness, such as to impart to the single bellow a
relatively low yielding resistance in the axial direction, and a
higher yielding resistance in the lateral direction.
One end of single bellow 26 is formed with a relatively thick
annular bead 26d received within an annular groove formed in wall
16 of the vacuum reservoir. The opposite end of the bellow is
formed with a relatively thick annular bead 26e received within an
annular socket formed in the respective end of the push rod 28.
Disposed within the vacuum reservoir 8 is a valve assembly,
generally designated 34. This assembly includes two one-way valves
oriented to produce a negative pressure at the opposite end of the
vacuum reservoir 8. In the example illustrated in FIG. 1, valve
assembly 34 produces a negative pressure at end 36 of the vacuum
reservoir 8, and a positive pressure at the opposite end 38. Thus,
end 36 of annular wall 16 defines a negative-pressure port, whereas
end 38 is open to the atmosphere. To produce this arrangement,
valve assembly 34 includes one-way valve 41 on the side of the
pumping opening 32 which faces the negative pressure port 36 and
which permits air flow only in the direction away from the
negative-pressure port; and a one-way valve 42 on the side of the
pumping opening which faces end 38 and which permits air flow only
in the direction towards the atmosphere.
One-way valve 41 is in the form of a resilient leaf 41a carried by
a mounting member 41b formed with an opening 41c which is normally
covered by the resilient leaf 41a. Mounting member 41b is of the
same external configuration and dimensions as the internal
configuration and dimension of annular wall 16, such that the
mounting member 41a may be press-fitted into the annular wall on
one side of the pumping opening 32. In the example illustrated in
FIG. 1 annular wall 16 is of cylindrical configuration, and
therefore mounting member 41b is of circular configuration. When
mounting member 41b is press-fitted within cylindrical wall 16,
reslient leaf 41a is on the pumping-opening 32 side of the mounting
member, such that the leaf blocks the flow through opening 41c in
the direction of the negative-pressure port 36, but permits the
flow through opening 41c only in the direction towards the
positive-pressure port 38.
One-way valve 42 is similarly constructed with a resilient leaf 42a
and a circular mounting member 42b formed with an opening 42c
covered by the resilient leaf valve 42a; however, it is
press-fitted into cylindrical wall 16 on the opposite side of the
pumping opening 32. Reslient leaf valve 42a is on the
positive-pressure port 38 side of the mounting member 42a, so that
it also permits air flow only in the direction towards the
positive-pressure port.
To facilitate assembling the two one-way valves, mounting member
41b is formed with a pair of depending pins 43, and mounting member
42b is formed with a corresponding pair of holes receiving pins 43
with a press-fit. In addition, the face of mounting member 42a
facing mounting member 40a is formed with a slanted surface, to
define a space 44 between the two mounting members aligned with
opening 32 for the air to flow through that opening.
A sound muffler member 46, also of cylindrical configuration, is
press-fitted into end 38 of the cylindrical wall 16 to muffle the
sounds produced by the air escaping through that port.
The negative-pressure port 36 includes a presettable device,
generally designated 50, which enables presetting the vacuum
produced at that port. Presettable device 50 may be of the same
construction as described, for example, in my U.S. Pat. No.
5,116,206. Briefly, it comprises a cylindrical plug 51 slidably and
rotatably movable within a cylindrical opening 52 formed in an
elbow fitting 53 attached to the negative-pressure port 36 and
passing through the casing 12 of the pump housing. The inner end of
plug 51 carries a sealing ring 54 normally engageable with the
inner face of elbow fitting 53. The outer end of the plug carries
an enlarged knob 55 permitting the plug to be manually rotated. An
arched leaf spring 56 passes through an opening in the outer end of
plug 51 so as to be rotatable with the plug. The outer ends of leaf
spring 56 is engageable with a plurality of discrete projections,
e.g., 58 of different heights arranged in a circular array around
the opening 52 in the elbow fitting 53.
The arrangement is such that the height of the projections 58
engaging the ends of the leaf spring 56 will determine the outward
force applied by the leaf spring to plug 51, and therefore the
degree of vacuum required to be produced within the vacuum
reservoir 18 to pull the plug inwardly to unseat its seal 54. So
long as the vacuum within the vacuum reservoir 18 is less than that
preselected by the rotary position of plug 51, seal 54 will be
firmly pressed by the leaf spring 56 against the inner surface of
the housing to seal opening 52. However, whenever the vacuum
exceeds the preset value, the vacuum will draw plug 51 inwardly
against the force of the leaf spring 56 to unseat seal 54, and
thereby to release the vacuum within the vacuum chamber 18 until
the vacuum reaches the level preset by plug 51.
Cover 10 of pump 2 is further formed with a socket 60 for receiving
an attachment connector 62 carried by the liquid collection
container 4 to facilitate attaching that container to the pump.
When the liquid collection container 4 is so attached to the pump
2, a side wall of the container engages the outer edge of end 38 of
the annular wall 16, thereby further muffling the sounds produced
by the air escaping from that end during the operation of the
pump.
The liquid collection container 4 is formed with a pair of opposed
side walls 63, 64, a pair of opposed end walls 65, 66, and a bottom
wall 67. The upper end of the container is open and is closed by a
cover 70. Projection 62 of the container received within socket 60
of the pump 2 projects from side wall 63, as seen in FIG. 1.
Cover 70 is also integrally formed with a vacuum inlet port 71 and
with a liquid inlet port 72, as shown in FIG. 2. The
negative-pressure port 36 of the vacuum reservoir 18 is connected
to vacuum inlet port 71 by a tube 73 having one end received in
elbow fitting 53 attached to the pump 2.
As shown in FIG. 2, the vacuum inlet port 71 of the liquid
collection container 4 is formed in a cover 70 at an angle with
respect to the cover; that is, the axis of the vacuum inlet port 71
is at an acute angle, preferably about 30.degree., to the plane of
cover 70. Liquid inlet port 72 in cover 70 is also at the same
acute angle with respect to the cover. The liquid inlet port 72 is
adapted to receive a tube (not shown) leading to the source of the
liquid to be drawn into the liquid collection container 4 by the
vacuum produced at the vacuum inlet port 71.
Forming the two ports 71 and 72 at an angle as illustrated in FIG.
2, rather than perpendicularly to the cover 70, permits the ends of
the tubes to which these ports are attached to assume a
substantially horizontal position with less danger of forming a
kink in the tube tending to obstruct the passage of air or liquids
therethrough. The foregoing is thus advantageous over the
conventional constructions wherein corresponding ports extend
substantially perpendicularly to their respective covers and
therefore are more likely to kink the tubes attached to them.
Also, fluid entering port 72 at an angle at high velocity, will hit
the side wall 66 of fluid collection container 4, running down the
wall without agitating the fluid already in the container. Vertical
fluid entry ports cause fluid turbulance which does not permit use
of the full volume of the fluid container, since the turbulant
fluid causes the shutoff valve 80 to float and shut off the vacuum
inlet port 71.
Cover 70 closing the upper end of the liquid collection container 4
is made of a semi-flexible material, and is integrally formed with
the two ports 71, 72. Cover 70 is also formed with a pair of
depending pins 74, 75 at one side of the vacuum inlet port 71 and
aligned with that port. The two pins 74, 75 are adapted to receive
an overflow shutoff valve 80 to block the vacuum inlet port 71 and
thereby to prevent overflow into that port of the liquid collected
in container 4.
The overflow shutoff valve 80 includes an annular shutoff section
81 closed at one end 82 and open at its opposite end 83, and a
mounting section formed with a pair of eyelets 84, 85 adapted to
receive with a press fit the pins 74, 75 of the cover 70. The above
sections of valve 80 are integrally formed of a single member of
elastomeric material and are connected together by a yieldable
juncture section 86. The overflow valve is mounted by press-fitting
the eyelets 84, 85 into the pins 74, 75, with the closed end 82 of
the shutoff section 81 facing the vacuum inlet port 71, and the
open end 83 of that section facing the interior of the
container.
FIG. 2 illustrates the normal position of the shutoff section 81,
wherein it will be seen that the closed end 82 of that section is
spaced from the negative pressure port 71, thereby passing the
negative pressure at that port into the interior of the container.
Accordingly, when the liquid inlet port 72 is connected by a tube
(not shown) leading to a liquid to be drawn away, such liquid will
be drawn via inlet port 72 into container 4. Should the level of
the liquid rise to the level of the shutoff section 81 of overflow
valve 80, that section will float on top of the liquid and will be
moved against the vacuum inlet port 71, to thereby prevent such
liquid from being drawn into the pump 2 via port 71.
Container 4 further includes a spacer wall 90 engaging the inner
surfaces of the two side walls 63, 64, to maintain the spacing
between them and thereby to mechanically reinforce the container.
The sprue 91 produced in the bottom wall 67 during the moulding
process may be retained, and not removed as is the general case,
and used as a projection for receiving the spacer 90.
For this purpose, spacer 90 is formed with a central tubular
section 92 to be press-fitted over the sprue 91 (or other
projection in the bottom wall 67), and an elongated spacer section
93 of a length equal to the width of container 4 between the two
side walls 63, 64. One end of spacer section 93 terminates in a
T-formation having perpendicular legs 94 to provide an extended
surface area engageable with the inner surface of side wall 63. The
opposite end of spacer section 93 is of reduced diameter,
preferably rounded, to engage the inner surface of the opposite
side wall 64, and thereby to firmly wedge the spacer wall 90
between the two side walls.
Spacer 90 thus supports the flexible cover 70 from collapsing
inwardly, and also supports the opposed side wall from being drawn
inwardly, when high vacuum is present within the container.
The height of spacer wall 92 is substantially less than the
complete height of the container 4. In the example shown in FIG. 2,
it is about one-half the height of the container, so as to provide
a common volume below the spacer wall for receiving the collected
liquid.
Casing 12 of the pump 2, includes a handle 96 for portability. The
bottom of casing 12 is formed with a pair of semi-circular recesses
97 extending transversely across its opposite ends for the complete
width of the casing. Recesses 97 receive elastomeric beads 98 of
cylindrical configuration which are press-fitted into these
recesses, and thereby serve as feet for supporting the pump and the
liquid collection container on any suitable horizontal surface.
Manner of Use
The manner of using the suction pump assembly illustrated in FIGS.
1 and 2 will be apparent from the above description. Thus, the
liquid collection container 4 is applied to the pump 2 by
press-fitting projection 62 of the container into socket 60 formed
in cover 10 of the pump 2. Tube 73 is then applied to elbow fitting
53 of the pump negative-pressure port 36, and to the vacuum inlet
port 71 of container 4. Another tube (not shown) is applied from
the liquid inlet port 72 of the container to the source of liquid
to be drawn into the container during the operation of the
pump.
The suction to be produced may be preset by presettable device 50,
as described above.
Electrical motor 20 is then energized which drives single bellow
26, coupled to the motor via eccentric 22 and push rod 28, through
expansion and contraction strokes. During the expansion strokes,
air is drawn into the single bellow from the interior of the vacuum
reservoir 18 via one-way valve 40 and pumping opening 32; and
during contraction strokes, the air is forced out of the bellow via
pumping opening 32 and one-way valve 42. Thus, a negative-pressure
is produced at port 36 of the vacuum reservoir 18.
This negative pressure at port 36 is communicated via tube 73 and
port 71 of the liquid collection container 4, to thereby produce a
vacuum within that container. This vacuum draws into the container
the liquid from the site receiving the tube (not shown) connected
to the liquid inlet port 72 of the container.
If the liquid should rise to the level of the shutoff member 81 of
overflow valve 80, the latter member will float to block the vacuum
inlet port 71 of the container, thereby preventing the liquid from
being drawn into the pump.
During this operation of the pump, muffler 46 received within the
positive pressure port 38 muffles the sound generated by the air
escaping through port 38. This sound is further muffled by the fact
that port 38 is engaged also by side wall 63 of the liquid
collection container 4.
The Embodiment of FIG. 3
FIG. 3 illustrates only the pump 2 of FIG. 1 but with the two
one-way valves 141, 142 oriented to reverse the pressures produced
at the two ends of the reservoir so that the reservoir, designated
118 now becomes a pressure reservoir. This can be done simply by
reversing the two one-way valves press-fitted into the vacuum
chamber. Thus, as shown in FIG. 3, one-way valve 141 (corresponding
to valve 41 in FIG. 1) is inserted into the pressure reservoir to
be located below opening 132, whereas the other one-way valve 142
is inserted to be located above the opening. In such an
arrangement, the port designated 136 now becomes a
positive-pressure port, whereas the end designated 138, normally
negative, is connected to the atmosphere.
In all other respects, the compressor pump illustrated in FIG. 3 is
constructed and operates in the same manner as described above with
respect to the suction pump of FIG. 1.
While the invention has been described with respect to one
preferred embodiment, it will be appreciated that this is set forth
merely for purposes of example, and that many other variations,
modifications and applications of the invention may be made.
* * * * *